Ground Self-Defense Force personnel undergo health checkups before they are dispatched to cull birds stricken with a strain of the avian flu virus at a chicken farm in Taragi, Kumamoto Prefecture, on Monday. | KYODO

Avian flu unlikely to sicken humans

Despite the desperate culling through Sunday night of thousands of birds at chicken farms in Kumamoto Prefecture, there is virtually no chance the avian flu outbreak will spread to humans, experts say.

From Friday to Sunday, an estimated 1,100 chickens raised at a farm in the town of Taragi were reportedly killed by the H5-type avian flu virus. It was the first domestic bird flu outbreak since 2011, in the city of Chiba.

Kumamoto Prefecture ordered that 112,000 birds at two farms be culled to contain the disease.

Experts voiced optimism that the virus, deadly as it is to birds, will have no impact on the public, let alone infect anyone.

According to the Food Safety Commission, eating poultry tainted with the virus poses no risk of infection, provided the meat is thoroughly cooked.

Even if ingested, the virus has almost no chance of compromising human cells, said commission official Suzuko Tanaka, citing the physical differences in protein molecules called receptors.

Furthermore, because the virus is highly vulnerable to acid, Tanaka said it most likely would be killed by the gastric acid in the human stomach. She stressed that poultry and eggs from all domestic farms undergo rigorous inspection before hitting the shelves.

Seiji Hayama from the Wild Bird Society of Japan agreed.

“As a general precaution, we advise people not to touch dead chickens with their bare hands,” said Hayama. “But there is little else they should keep in mind, perhaps except to refrain from visiting the Kumamoto farm in question and to maintain their usual hygiene routines.”

Hayama pointed out that the virus rarely spreads to humans, unless they “actively seek contact with infected chickens,” such as through their feathers, blood and feces. Though rare in Japan, infections have happened in other Asian countries, where unprocessed birds are sold alive in street markets, Tanaka of the Food Safety Commission said.

Because the exact virus detected at the Kumamoto farms has yet to be determined, the H5N1 strain — one of the most deadly — has not been ruled out.

But, according to the health ministry, no human infections stemming from the strain have ever been reported in Japan. The H5N1 bird flu has turned up in other Asian countries, including Indonesia, Cambodia and China.

Since November 2003, 163 of the 195 people infected with H5N1 have died. Common symptoms include fever, diarrhea and multiple organ failure.

As a safety precaution, the ministry warns against having direct physical contact with dead or dying wild birds. Aside from the flu virus, they might also be carrying potentially harmful germs.